Comets and asteroids

Asteroid 27 Euterpe reaches opposition on 14 March in the constellation of Virgo

Asteroid 27 Euterpe reaches opposition on 14 March when it will appear as a mag. +9.4 object in Virgo, located close to the VirgoLeo border and just west of the large asterism known as the Bowl of Virgo. During March the asteroid’s track begins within the bowl just to the north of mag. +3.6 Zavijava (Beta (b) Virginis). By the month’s end, Euterpe crosses the border into Leo, ending up close to mag. +4.0 Sigma (s) Leonis.

Reaching mag. +9.4 at opposition puts Euterpe around a magnitude fainter than the best it can achieve at a perihelic opposition – an opposition which occurs when the asteroid is at the closest point in its orbit to the Sun. Its elliptical orbit takes it out as far as 2.75 AU from the Sun and in as close as 1.94 AU. An orbit for Euterpe takes 3.59 years to complete. The body’s spin has been determined from accurate light curve measurements to be 10.4 hours. 27 Euterpe is a stony object measuring almost 100km across. A two-dimensional profile dimension of 124x75km was determined from an occultation observation. Its orbit lies within a region of the asteroid belt known as the inner asteroid belt. There are various ways of subdividing the asteroid belt but one convenient method uses natural resonance gaps within the orbits known as Kirkwood gaps to provide definition. The inner main belt describes bodies whose orbits mostly lie closer to Mars out to 2.5 AU. This asteroid is the parent body of a group of asteroids known as the Euterpe family, all of the 400 or so members of this family being stony asteroids like Euterpe.

As March begins, Euterpe shines at mag. +9.7, making it ideal for small scope views. It brightens for opposition and then fades back to mag. +9.9 on the 31st when it lies 1.6˚ to the east-northeast of Sigma Leonis.